sat高手进.我需要解释.语法题

sat高手进.我需要解释.语法题
Question
1) Although he was not elected as the captain,Omar has become the team leader,him being the most vocal and respected player on the team
A) has become the team leader,him being
B) is being the team leader because of his being
C) is the team leader for being
D) has become the team leader because he is
E) has become the team leader for having been
Answer:D(Why not )
2) Most students thought that the new parking policy was as restrictive,if not more,than the previous policy.
A) as restrictive,if not more,than
B) as restrictive,if not more,as
C) perhaps as restrictive,but perhaps more restrictive,as
D) as restrictive as,if not more,than
E) as restrictive as,if not more restrictive than
Answer:E (Why not )